Piston construction



May 17, 1966 w. F. ISLEY PISTON CONSTRUCTION Filed Jan. 9, 1964 INVENTOR. WALTER E ISLEY lay/444i 7 AT TORNEYS United States Patent O 3,251,349 PISTON CONSTRUCTION Walter F. Isley, Grosse Pointe, Mich., assignor to Continental Aviation and Engineering'Corporation Filed Jan. 9, 1964, Ser. No. 336,680 Claims. (Cl. 123-32) The present invention relates to internal combustion engines, particularly to such engines in which the combustion chamber is arranged entirely. or substantially entirely within the face of the piston and more particularly to a new piston construction for such engines.

The advantages-of providing the combustion chamber within the face of the piston have been known for some time. It has also been proventhat the'most" desirable shape for such a combustion chamber is in the form of the major portion of a sphere. There are, however, certain inherent disadvantages in providing such a piston construction which have not been heretofore satisfactorily overcome. Forming the combustion chamber cavity in the shape of the major portion of a sphere produces a thin lip of material on the face of the piston at the entrance to the combustion chamber. This lip or edge has the tendency to crack or break off under the high temperature conditions produced in the combustion chamber during operation of the engine. The proximity of the combustion chamber to the area of the piston ring grooves causes thermal expansions and distortions especially in the vicinity of the top groove which in turn can cause wear and scoring of the cylinder walls.

The present invention overcome these difficulties by providing an insert member constructed of high temperature material and formed to define the lip of the combustion chamber as well as the top ring groove. The piston member is preferably molded around this insert member. In this way the piston can be constructed of relatively light and low temperature materials and those areas most affected by high temperatures are protected.

It is an object of thepresent invention to produce a more eificient internal combustion engine by providing a piston assembly for such an engine comprising an insert member defining the entrance to the combustion chamber provided in the face of the piston.

It is another object of the present invention to reduce thermal cracking of the lip or edge defining the combustion chamber of those pistons having the combustion chamber entirely or substantially entirely Within the face of' the piston by providing means for constructing such lip or edge of high temperature material.

It is another object of the present invention to reduce the effects of high temperatures on the top ring grooves of pistons having the combustion chamber provided in the face thereof by providing an insert member of high temperature material forming the top ring groove.

Still further objects and advantages of the present invention will readily occur to one skilled in the art to which the invention pertains upon reference to the following drawings in which like reference characters refer to like parts throughout the several views and in which:

FIG. 1 is a top elevational view of a piston of the present invention,

FIG. 2 is a cross sectional view taken substantially on line 2-2 of FIG. 1, and

FIG. 3 is a fragmentary cross sectional view taken substantially on line 3-3 of FIG. 1.

Description Now referring to the drawings for a more detailed description of the present invention, a preferred piston is illustrated as having a head 12 and a skirt 14. The head 12 is provided with a substantialy planar face 16.

A cavity 18 is provided in the face 16 and extends "ice into the head 12. The cavity18and an insert member 20 which will'bedescribed in greater detailbelowdefine a combustionchambercavity. 22 which as shown is.preferably in the form of the major portion of a sphere. A substantially radial groove 24-is formed in the insert'member 20 as can best be seen in FIGS. 1-2 to direct fuel from an injector nozzle (not shown) into the. combustion chamber cavity 2-2.

The skirt 14 is prefera'bly hollowasr shown to provide an -axially extending re'cess26. Wristpin'bosses' 28 extend radially inwardly from opposite sidesof the recesss 26'an'd are provided :with axially aligned openings 30. Theopenin'gs' 30 are adapted to receive awrist pin (not shown).

The head 12 is -provided with'anannularexterior surface 32 and 'a plurality of axially spaced ring grooves 34 are provided in the surface 32. The insert member 20 defines a top ring groove 36. Each of the grooves 34 and the top ring groove 36 are adapted to carry conventional piston rings (not shown).

The insert member 20 is preferably constructed of a high temperature material such as stainless steel or the like and comprises a medial portion 38 which defines the upper portion of the combustion chamber cavity 22 and the groove 24 as well as the thin edge or lip 40 which forms the entrance to the combustion chamber cavity 20. Spokes or arms 42 radiate outwardly from the medial portion 38 through the head 12 as can best be seen in FIGS. 1 and 3 and are joined at their free ends with an annulus 44. The top ring groove 36 is formed in the annulus 44.

The piston 10 of the present invention is preferably manufactured by positioning the insert member 22 in a suitable mold by the extended portion of the annulus 44 shown by dotted lines in FIG-S. 2-3. The piston 10 is then molded around the insert member 22 and the annulus is machined to remove the excess and to form the top ring groove 36.

It is apparent that the present invention provides a piston which is constructed of high temperature and expensive materials in only those areas where such materials are needed. The lip 40 which ordinarily has a tedency to crack or break off under the extremely high temperatures produced in the combustion chamber cavity 22 has been strengthened. The top ring groove 36 which has a tendency to warp, wear or distort to cause scoring of the cylinder walls by the top ring'has been constructed of high temperature materials to reduce this tendency.

It is also apparent that although I have described but one embodiment of the present invention many changes and modifications can be made without departing from the spirit of the invention as expressed .by the scope of the appended claims.

I claim:

1. In an internal combustion engine a piston assembly comprising (a) a piston having a head portion,

(b) a substantially hemispherical combustion chamber cavity being provided in said head portion and a plurality of axially spaced piston ring grooves being provided on the exterior surface of said head portion,

(c) an insert member constructed of a high temperature material having a medial portion defining the upper part of said combustion chamber cavity and an annular portion defining at least one of said piston ring grooves,

(d) said insert member further defining a substantially radial fuel receiving groove opening to the upper portion of said combustion chamber cavity.

Patented- May I 1 7, 1966 2. The piston assembly as defined in claim 1 and in which said annular portion defines the uppermost of said piston ring grooves.

3. The piston assembly as defined in claim 1 and in which said medial portion of said insert member is connected with said annular portion by a plurality of spokes extending radially through said head portion of said piston.

4. The piston assembly as defined in claim 1 and in which (a) said head portion is provided with an upper planar surface,

(b) said insert member is provided with a circular lip portion defining the entrance to said combustion chamber cavity, and

(c) the upper portion of said lip portion being substantially co-planar with said upper planar surface of said head portion.

5. The piston assembly as defined in claim 4 and in which said fuel receiving groove extends radially and downwardly through said lip portion.

References Cited by the Examiner UNITED STATES PATENTS 1,946,081 2/1934 Koch 92-213 2,880,044 3/1959 Cofiey 92213 3,152,523 10/1964 Whitfield et al 92-224 FOREIGN PATENTS 895,884 4/ 1944 France.

897,918 6/ 1944 France. 1,288,819 2/1962 France.

741,173 11/1955 Great Britain.

MARK NEWMAN, Primary Examiner.

RICHARD B. WILKINSON, Examiner. 

1. IN AN INTERNAL COMBUSTION ENGINE A PISTON ASSEMBLY COMPRISING (A) A PISTON HAVING A HEAD PORTION (B) A SUBSTANTIALLY HEMISPHERICAL COMBUSTION CHAMBER CAVITY BEING PROVIDED IN SAID HEAD PORTION AND A PLURALITY OF AXIALLY SPACED PISTON RING GROOVES BEING PROVIDED ON THE EXTERIOR SURFACE OF SAID HEAD PORTION, (C) AN INSERT MEMBER CONSTRUCTED OF A HIGH TEMPERATURE MATERIAL HAVING A MEDIAL PORTION DEFINING THE UPPER PART OF SAID COMBUSTION CHAMBER CAVITY AND AN ANNULAR PORTION DEFINING AT LEAST ONE OF SAID PISTON RING GROOVES, (D) SAID INSERT MEMBER FURTHER DEFINING A SUBSTANTIALLY RADIAL FUEL RECEIVING GROOVE OPENING TO THE UPPER PORTION OF SAID COMBUSTION CHAMBER CAVITY. 